Meeting Abstract
Blue crabs, Callinectes sapidus, support Louisiana’s third largest commercial fishery. Louisiana has led the nation in blue crab landings for 7 of the last 10 years. Landings in 2014 totaled 39.4 million pounds for a dockside value of $61 million. Although blue crabs are not currently overfished, fishery-independent estimates of abundance have indicated a decline in recent years and are now below long-term averages as well as target reference points. Management efforts for the fishery have been hindered by an incomplete knowledge of the migration patterns and fishing mortality of Louisiana blue crabs. In March 2016, we began a mark-recapture study to examine these trends in the Terrebonne and Pontchartrain basins. In collaboration with local fishermen, we have tagged 2,500 crabs, with a final target number of 6,000 female blue crabs from multiple salinity zones. Tags (1 x 2 in.) lay flat across the carapace and are secured by steel wire wrapped around the lateral spines. Recapture data have been obtained from commercial and recreational crabbers and shrimpers, state fisheries agencies, and the public. In general, tagged female blue crabs moved seaward, consistent with our understanding of the spawning migration from studies on the Atlantic Coast. Recapture rates are also being used to assess spatial and temporal patterns in fishing mortality. Finally, recently molted females from each tagging area are collected, and their sperm stores examined to determine if heavier fishing of males affects sperm abundance and thus, reproductive success. This information, combined with tag-recapture results, will be directly applicable to Louisiana blue crab management plans, stock assessments, and will ensure the continued sustainability of the Louisiana blue crab fishery.
